GaussianBasisGenerator.h

/* Copyright 2019 Kristofer Björnson
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


#ifndef COM_DAFER45_TBTK_GAUSSIAN_BASIS_GENERATOR
#define COM_DAFER45_TBTK_GAUSSIAN_BASIS_GENERATOR

#include "TBTK/GaussianState.h"

#include <unordered_map>
#include <vector>

#include <libint2.hpp>

namespace TBTK{

class GaussianBasisGenerator{
public:
    GaussianBasisGenerator();

    GaussianBasisGenerator(
        const GaussianBasisGenerator &gaussianBasisGenerator
    ) = delete;

    ~GaussianBasisGenerator();

    GaussianBasisGenerator& operator=(
        const GaussianBasisGenerator &rhs
    ) = delete;

    std::vector<GaussianState> generateBasis();
private:
    std::vector<GaussianState> basisSet;

    libint2::BasisSet libintBasisSet;

    std::unordered_map<size_t, std::vector<size_t>> libintShellPairList;

    std::vector<
        std::vector<std::shared_ptr<libint2::ShellPair>>
    > libintShellPairData;

    std::vector<libint2::Atom> atoms;

    static unsigned int instanceCounter;

    void initialize();

    void initializeBasisSet();

    void computeShellPairs(double threshold = 1e-12);

    void calculateSingleParticleTerms(
        libint2::Operator o,
        std::function<
            void(
                std::complex<double> value,
                unsigned int linearBraIndex,
                unsigned int linearKetIndex
            )
        > &&lambdaStoreResult
    );

    void calculateTwoBodyFockTerms();
};

};  //End of namespace TBTK

#endif